package provide xotcl::registry::registry 0.8

package require xotcl::trace
package require xotcl::rdf::triple
package require xotcl::rdf::tripleRecreator
package require xotcl::actiweb::agent
package require XOTcl 1

namespace eval ::xotcl::registry::registry {
    namespace import ::xotcl::*

    Class Registry -superclass Agent

    Registry instproc init args {
	next
	my exportProcs register query queryProperty
	RDFParser [self]::parser
	TripleVisitor [self]::tripleVisitor -parser [self]::parser
	[self]::tripleVisitor descriptionAsBag 0
	my array set services {}
    }

    Registry instproc register {rdfScript} {
	#my showCall
	[[self]::tripleVisitor set parser] parse $rdfScript
	[self]::tripleVisitor interpretNodeTree [self]::parser::topNode
	[self]::tripleVisitor resetWithoutDB
	foreach serviceTriple [[self]::tripleVisitor::db queryPredicate \
				   "http://nestroy.wi-inf.uni-essen.de/schema/service#name"] {
	    set service [$serviceTriple object]
	    if {[info exists services($service)]} {
		puts stderr "we have already such a service '$service'"
		# hier koennte man ueberlegen, den service zu loeschen oder nicht
		# zZT: loesche altes service
	    }
	    puts stderr "REGISTRY: registering $service with [$serviceTriple subject]"
	    my set services($service) [$serviceTriple subject];
	}
    }

    Registry instproc query {service} {
	my showCall
	if {[info exists services($service)]} {
	    set s [my set services($service)]
	    return [[Place getInstance]::rdfCreator createFromTriples [[self]::tripleVisitor::db querySubject $s]]
	}
    }

    Registry instproc queryProperty {args} {
	# returns first service with matching properties
	my showCall
	foreach s [my array names services] {
	    set success 1
	    foreach {att value} $args {
		set t [[self]::tripleVisitor::db queryPredicateOnSubject $att [my set services($s)]]
		if {$t eq "" || [$t object] != $value} {
		    set success 0
		    break
		}
	    }
	    if {$success} {
		set r [my query $s]
		return $r
	    } else {
		return ""
	    }
	}
    }

    namespace export Registry
}

namespace import ::xotcl::registry::registry::*